Screw-cutting die.



No. 764,410. PATENTED JULY 5, 1904.

H. B. ADT. v SCREW CUTTING DIE.

APPLICATION FILED DEO.5, 1903.

III

INVENTOR f fiIVaroLZ/Qdlt ll! 1 I M1 M1. 2 I OMM MW ATTORNEY$ No- 764,410. PATENTED JULY 5, 1904. H. B. ADT.

SCREW CUTTING DIE,

APPLICATION nnnn 1230.5. 1003. no MODEL.

2 8HBETB-SHEBT 2.

J l T n WITNESSES INVENTOR. V )iGumn-o BLdaLC ATTORNEYS UNITED STATES Patented July 5, 1904.

PATENT OFFICE.

- HOWARD E. ADT, OF NEW HAVEN, CONNECTICUT, ASSIGNOR TO GEO- METRIC DRILL COMPANY, OF WES'IVILLE, CONNEC'IICUT, A COB.-

PORATION OF DELAWARE.

v SCREW-CUTTING DIE.

SPECIFICATION forming part of Letters Patent No. 764,410, dated July 5, 1904.

Application filed December 5, 1903 Serial No. 188,937. (No model.)

i To rt/l whom it may concern:

Be it known that I, HOWARD E. ADT, a citizen of the United States of America, residing in the city of New Haven, in the county of New Haven, State of Connecticut, have invented Improvements in Screw-Cutting Dies, of which the following is a specification.

My invention relates more particularly to self-opening screw-cutting dies and also taps of the pull-off typethat is, in which when the desired length of screw has been cut the opening die is used on a screw-machine turret it is customary to provide a projection on the turret-carriage to act on a pin on the cam of the tool to close the die automatically as the turret revolves, thus bringing the cutters to their correct position for cutting as they are brought around to their work; but in some makes of automatic screw-machines the turret is constructed to revolve in the reverse direction from the ordinary hand-operated turret. Again, in some machines the die-head is to be operated on a live spindle and the dies closed while in motion, whereas on other machines the work revolves. To meet these varying conditions, I have invented the construction of reversible die, which I will now describe. My invention also embraces certain other improvements in the construction of the die, as hereinafter set forth. Certain features of my invention are applicable also to taps, as will be readily understood.

In the accompanying drawings, Figure 1 is a longitudinal section on the line 1 1, Fig. 4:, of a die constructed according to my invention.

Fig. 2 is a longitudinal section on the line 2 2, Fig. 4. Fig. 3 is a transverse section on the line 3 3, Figs. 1 and 2. Fig. 4: is a front end view with the cutter-retaining plate removed. Fig. 5 is a side View, and Fig. 6 an end view.

A is the stock, with a shank A of suitable construction, and B is the cutter-head, iittingover a central collar A on the stock and also guided by longitudinal pins a a, secured in the stock, Figs. 2, 3, and 6, and projecting into holes in the cutter-head. The latter is normally held up to the stock by springs 19, Fig. 1, around headed pins 1, passing through the stock and threaded into the cutter-head B. The latter is radially slotted for the reception of the cutters E, (four in the presentinstance,) which are held in place longitudinally by the annular front plate F, suitably secured by screws to the cutter-head. Immediately back of the cutters the slots are undercut for the reception of plates E, Figs. 1 and 2,which carry pins 0, projecting on opposite sides of the plates. On the front side of the plate the pins passinto holes in the cutters, which when in place are thus carried by the plates. Behind the plates E springs a are interposed between the closed inner ends of the slots and the backwardlyprojecting pins, so that these springs c thus constantly tend to push the plates and their cutters radially outward against theinner surface of the cam-ring C. This cam-ring C, which is mounted upon the cutter-head B and can turn thereon to a limited extent, has its inner face of the undulating cam form shown in Fig. 4, so that it can push the cutters E inward to their operative positions or allow them to move back to the open position (under the action of their springs c) by the turning of the cam-ringeither to the right or to the left, as the adjustment may require.

In the back of the cam-ring 1 form an annular chamber G for the reception of acoiled spring S, Figs. 1, 2, and 3, which at one end bears against a block H, secured to the camring, and at the other end bears against a pin or projection I), carried by a plate B, which is secured to the cutter-head B. The stopblock H is recessed at h to receive the inner end of the locking-pin T, whichis carried by a ring'R adjustable rotarily on the stock A. I prefer to thread this ring R onto the stock, as shown at Figs. 1 and 2. I also prefer to provide on the ring R a sleeve 2., Fig. 2, which passes through a slot r in the stock, Fig. 6, and through which passes a rear extension of the locking-pin T. Screw-pins n a, threaded through the stock, project into the slot 9* to be brought to bear against diametrically opposite sides of the sleeve Land so adjust the position of the locking-pin Twith relation to the block H, and thereby determine the position of the cam-ring Cwhen it is locked to the cutter-head to hold the cutters in their closed or operative positions.

The inner end of the locking-pin T, which projects into the recess 70 of the stop-block H, is slabbed at one side, as shown in Figs. 2 and 3, so that by the turning of the pin T with its rounded or its slabbed side to the acting edge of the recess 72 the cutters may be held in positionfor either the roughing or finishing cut. The pin T is provided at its rear end with a handle T, by which a semirevolution may be conveniently imparted to the pin T, stops n a on the back of the stock serving to limit this movement, Figs. 2, 5, and 6.

The cam is provided externally with a handlever C and also with a pin C for the action of the closing-bar on the turret-carriage.

When the die-head is to be used on a turret where it is desirable to have the cam rotate to the right to open and to the left, Fig. 3, to close the cutters, the cam-spring S is placed in the part of the chamber to the left, Fig. 3, bearing against the abutment afforded by the left-hand end of the block H; but when the cam is to move in the opposite directions the spring S will be placed in the right-hand part of the chamber, Fig. 3, between the pin 5 and the abutment afforded by the right-hand end of the stop-block H. Then the lockingpin T will bear against the block H at the right-hand side of the recess 7b. In the drawings the die-head is shown as adjusted to have the cam-ring turn to the right to open, as indicated by the upper arrow-mark in Fig. 5, on the upper degree-mark on the cam-ring in line with the mark on the ring R and the micrometer adj ustment-marks on the stock A. When the opening or cam-spring S is changed to the other chamber, the lower of the two degreemarks in Fig. 5 will be brought opposite the line-mark on the ring R with the arrow indicating the direction of movement of the cam for automatic opening.

In operation when the desired length of rod has been threaded by the tap the longitudinal feed of either the die or the rod being threaded is arrested by suitable means, while the rotary motion of the tool or the work continues, with the result that the Work thereupon automatically pulls the cutter-head away from the stock, and thereby releases the cutter-holding rotary cam from the locking-pin T, and under the action of the spring S the cam turns-and the cutters open, or, in other words, move back from their operative positions.

The feature of threading the rotarily-adjustable ring R upon the stock is not claimed in this case, as it is claimed in a prior application for patent filed by me November 12, 1903, Serial No. 180,922.

I claim as my invention- 1. A stock and a cutter-head, having a projection, in combination with a reversible rotary cam having two opposite abutments, cutters controlled by the cam, a locking device to lock the cam and cutter-head and a spring adapted to be placed between the cutter-head projection and either abutment on the cam, substantially as and for the purpose described.

2. A stock and a. cutter'head having a projection, in combination with a reversible ro tary cam having an annular chamber with two opposite abutments, cutters controlled by the cam, a locking device to lock the cam and cutter-head and aspring adapted to be placed in said chamber between the cutter-head projection and either abutment on the cam, substantially as and for the purpose described.

3. A stock and acutter-head, having aprojection, in combination with a reversible rotary cam having two opposite abutments, cutters controlled by the cam, a locking device to lock the cam and cutter-head and a spring adapted to be placed between the cutter-head projection and either abutment on the cam, the cutter-head being movable longitudinally with relation to the stock to release the locking means. 1

4. A stock and a cutter-head, having a projection in combination with a reversible rotary cam having an annular chamber and a recessed block therein, a locking-pin on the stock to engage the recessed part of the block, cutters controlled by the cam, and a spring adapted to be placed between the cutter-head projection and either end of said block.

5. A stock, cutter-head and rotary cam and cutters controlled by the latter with a rotarily-adjustable ring on the stock carrying a slabbed locking-pin for the cam, said pin being revoluble to change from roughing to finishing cut and adjusting-screws on opposite sides of the locking-pin to adjust the pin-carrying ring on the stock.

6. A stock, cutter-head and rotary cam and cutters controlled by the latter with a rotarily-adjustable ring on the stock, carrying a locking-pin for the cam and a sleeve for the pin projecting into the stock, said pin being slabbed and revoluble in the sleeve to change from roughing to finishing cut, and adjusting-screws 1n the stock to bear on opposite sides of the sleeve 7. A stock with a slotted eutter head and In testimony whereof Ihave signed my name cutters therein, plates carrying pins projectto this specification in the presence of two subing on opposite sides of the plates, receiving scribing Witnesses.

the cutters on the forward sides and form- HOWARD E. ADT. 5 ing abutments for springs onthe rear sides Witnesses:

of the plates and acam-ring to act on the eut- L. W. BEEGIIER,

W. A. LEONARD.

ters. 

